Expansible-collapsible element



G. B. DUFFIELD EXPANSIBLE COLLAPSIBLE ELEMENT 1 Filed April 29. 1926Feb. 28, 1928.

Patented Feb. 28, 1928.

UNITED STA TES PATENT] OFFICE.

GEORGE BETHUNE DUFFIELD, OF DETROIT, MICHIGAN, ASSIGNOR TO DETROITLUBRI- CA'IOR COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

EXPANSIBLE-COLLAPSIBLE ELEMENT.

Application filed April 29, 1926. Serial No. 105,408.

My invention relates to new and useful improvements inexpansible-collapsible elements, and particularly of that generalcharacter or type adapted to be subjected .to. pressure or thermostaticconditions, for the purpose of operating a desired device or mechanism,or as a packing or seal for rods, valve stems, and the like, or as aflexible coupling between tubes, and consisting generally of an annularor tubular shell of thin metal formed with parallel circumferentialcorrugations comprising inner and outer bends joined by intermediatewall portions which extend 111 a general direction trans versely of theelement, whereby the latter is rendered expansible and collapsiblelongitudinally, and may be flexed laterallyof its longitudinal axis.

It sometimes occurs that elements of the character mentioned arerendered inactive or inoperative, due to the fact through continuoususe, or from being subjected to excessive pressures, the metal of thebends of the corrugations becomes fatigued to a point destroying orimpairing the resilience of the bends, which results in permanentcollapse of the element at one or more points, thus redueing its life orimpairing its operation.

One object of the invention is to provide means which will obviate theobjectionable results just stated, and contemplates im- "proved meansfor limiting collapse of the bends of the corrugations to any suchextent as might result in destruction or reduction of the elasticity orthe resilience of the element.

A further object of the invention is to provide such an element withimproved means for limiting the collapsing movement thereof, so as toprevent the bends from being collapsed or flexed beyond a point whichwould result in the metal of the bends being subjected to over-strains,whichwould result in a permanent set or fatigue of the metal.

A further object is to provide improved reenforcing means for thepurposes above stated, which may be readily applied to the element.

Other objects and the attending advantages will be apparent from thedescription to follow hereinafter.

lhe invention consists in the improvements to be more fully describedhereinafter,

and the novelty of which will be particularly pointed out and distinctlyclaimed.

I have fully and clearly illustrated my invention in the accompanyingdrawings to be taken as a part of this specification, and wherein-Figure 1 is a longitudinal sectional View through a structure embodyingmy invention;

Fig. 2 is a section on the line 2-2 of Fig. 1;

Fig. 3 is an enlarged detail sectional view of a portion of the wallshown in Fig. 1;

Fig. 4 is a view similar to Fig. 1, showing another embodiment orapplication of the same invention;

Fig. 5 is an enlarged detail view similar to Fig. 3, but showing aportion of the embodiment shown in Fig. 4, and

Fig. 6 isa detail view of the reenforcing element.

Referring to the drawings by characters of reference, A designates apreferred form of an expansible-eollapsible element, consisting of atubular metal shell 1, substantially cylindrical in general contour. Theshell 1 may be and preferably is closed at one end by an integral head2, preferably in the form of a boss consisting of a transverse wallmember 3 having a circumferential cylindrical portion 4, joined'at itsedge with the cylindrical shell 1 of the element. The oppositeend of theelement is provided with a longitudinal cylindrical extension or flange5, by which the element is adapted to be secured or attached to anysuitable element or support, not shown. The head 2, heretoforementioned, is preferably of thicker metal than that composing thecylindrical shell 1, and the annular portion l tapers into the metal ofthe shell, as indicated at 6. The element in its preferred form iscomposed ofa suitable metal alloy, for example, copper, or alloy ofcopper and zinc, which, in its preferred el'nbodiment, is drawn bysuitable die mechanism to a thickness of approximately .007 of an inch.The body of the element is provided with circumferential corrugations 7,by which the element is rendered longitudinally expansible andcollapsible. The corrugations 7 comprise alternate inward, flexible andresilient bends 8 and outward flexible and resilient bends 9,

connected by intermediate wall portions 10, the latter extending in ageneral direction transversely of thevelement. These corrugations 7,including the bends 8, 9, and the depth of the walls 10, are preferablypro portioned according to the diameterof the element. For example, inan element of 2 inches outside diameter,'the inside diameter of theelement may be approximately 1.72 inches, and the depth of thecorrugation .344

inch, the bends of the corrugations being curved and struck on a radiusof approximately .045 inch.

It will be understood, that while I show and describe a specific form ofcorrugated, expansible-collapsible element as being one to which myinvention is readily applicable, I wish it understood that the inventionis not limited thereto, the same being shown and described only for thepurpose of disclosing a preferred embodiment.

The element% adapted to be subjected to either internal or externalpressure, and is either collapsed or expanded, as the case may be, toactuate a desired device or mechanism, and the corrugations are sospaced that they will have the necessary resilience to give the elementthe desired extent of movement when actuated, the resilience of themetal in the bends 8, 9 acting to return the element to a normalposition or condition of rest. In practice it sometimes occurs that theelement is collapsed to such an extent as to flex the bends beyond theirpoint of resilience, which results in fatiguing the metal, and eithercausing the device to take a permanent set, or impairing its resilience.

According to my present invention, I provide improved means whereby theelement is prevented from being collapsed to a point beyond the normallimit of resilience of the bends, thereby preventing continued use orexcessive pressures from fatiguing the metal to the objectionable extentabove mentioned.

In the preferred embodiment, this means consist of an annular memberllarranged in the bend of a corrugation, and maintained in contact withthe central portion of the bend, as clearly shown in Figs. 3 and 5. Th smember 11 preferably consists of an annulus or ring, consisting of aflexible helix made from a= wire coil 12, the ends of which are providedrespectively, with a hook 13 and an eye 14, by means of the helix may beconnected to eachother to form the ring.

The helix is upreferably made of a body diameter less than thetransverse width of the bend of the corrugation, so that clearancespaces 15 are provided between the opposite sides or faces of the ringand the inner faces of the side portions of the bends 8, 9. The bodythickness of the helix is preferably such that upon collapsing movementof the side portions of the bends, the inner which the ends of b facesof the latter will contact the o posite sides of the ring within thelimit of resilience of the bend, whereby excessive collapse of thecorrugation, and consequently of the expansible-collapsible element, andfatigue of the metal in the bend, are prevented. It will be understoodthat the body thickness of the helix will be ance with the internaldiameter of the bend of the corrugation to which the helix is applied.-For example, in an element'of the size heretofore mentioned, namely, 2%inches, wherein the bend is formed on a radius of approximately .045inch, the body of the helix is formed on a radius of approximately .040inch, whereby the helix is of a diameter approximately .080 inch.

The helix may be made of any suitable material which transverse rigidityto resist or limit the collaps'ng movement of the bend of thecorrugation. In the preferred form the helix is made of a suitable metalwire, which when coiled will assure the helix being circumferentiallyresilient or elastic, so that the helix may be stretched.

In the forms shown wherein the reenforcing member is applied within theinner bends 8, the wire of the helix is coiled in such manner that thehelix may be stretched to enlarge its diameter sufficiently to pass overthe element, and then contracts to such diameter as will cause it tosnugly seat within the bend against the central portion thereof, asclearly shown in Figs. 4 and 5. In the case just stated, the diameter ofthe helix is so determined that when it is in place within the innerbends 8, it will be held in the position stated by its own resiliency.In forming the helix for the inner bends 8, it is made of such diameterthat when it is adusted in position, as shown in Fig. 5, the transversediameter of the helix will be such, as to bear the proportionsheretofore stated, and provide the proper clearance spaces 15, asdescribed. I

In the case where the helix is to heapplied to the inner faces of theouter bends 9, as shown in Figs. 1 to 5, inclusive, it may be of thesame general form as heretofore described, but is made of such atransverse overall diameter as to be slightly greater in diameter thanthe diameter of the element etween opposite points on the inner faces ofa bend, and the strandof wire is so coiled as to leave suflicient spacebetween the turns to permit the turns to be resiliently collapsed towardeach other. When the helical ring is to be applied to the inside of theouter bend or corrugation, the helix may be collapsed or flexed in anydirection to permit it being entered within the opening of the bend, andit then is moved outward within the bend until it contacts the centralportion thereof, as shown in the drawings. When in position will givethe same suflicient proportioned in accordwithin the bend, the helix isheld under compression, that is, is tending to expand, due to theproportions and coil arrangement above mentioned, and is thereby heldagainst the central portion of the bend to provide the clearance spaces15 above mentioned.

From the foregoing it will be seen that when the coil is to be appliedto the bend of the inner corrugations 8, it is made sufiiciently elasticas to tend at all times to contract, so as to grip the bend, but when itis to be applied to the inside of the outer bends or corrugations 9, itis made so as to be under compression, and therefore tending at alltimes to expand. However, in either case, that is, whether applied tothe bends of the inner corrugations or of the outer corrugations, thehelical reenforcing member takes such position as to automatically setitself in proper position, and prevents such collapse of the sideportions of the bends as might result in impairment of resilience, orfatiguing of the bend.

What I claim and desire to secure by Letters Patent of the United Statesis 1. An expansible-collapsible element comprising a tubular metallicshell having circumferential corrugations formed of inward and outwardbends connected by intermediate transverse wall portions, and meanslocated in certain of said bends to limit collapse thereof in adirection longitudinally of the shell, said means comprising a flexibleand longitudinally resilient helix arranged in engagement with the innerface of a bend.

2. An expansible-colla sible element comprising a tubular metallic shellhaving circumferential corrugations formed of inward and outward bendsconnected by intermediate transverse wall portions, and means located incertain of said bends to limit collapse thereof in a directionlongitudinally of the shell, said means comprising a helical annulusarranged in engagement'with the inner face of the bend.

3. An expansible-collapsible element comprising a tubular metallic shellhaving circumferential corru ations formed of inward and outward ben sconnected by intermediate itransverse wall ortions, and means located incertain of said bends to limit 001- lapse thereof in a directionlongitudinally of the shell, said means comprising a helix arranged inengagement with the inner face of the bend, said helix being of suchthickness in a direction lengthwise of the element as to provideclearance spaces between the helix and the lateral portions of the bend,but adapted to be engaged by said lateral portions within the limit ofresilience of the metal of the bend.

4. Anexpansible-collapsible element comprising a tubular metallic shellhaving circumferential corrugations formed of resilient inward andoutward bends connected by intermediate transverse Wall portions andmeans located in certain of said bends to limit collapse thereof in adirection longitudinall of the shell, said means comprising an annu armember in the form of a helix arranged in engagement with the middleportion of the inner surface of the bend, said member being of suchthickness lengthwise of the element as to provide clearance spacesbetween the said member and the lateral portions of the bend, butadapted to be engaged by said lateral portions within the limit ofresilience of the metal of the bend.

5. An eXpansible-collapsible element comprising a tubular metallic shellhaving circumferential corrugations formed of resilient inward andoutward bends connected by intermediate transverse wall portions,

and means located in certain of said bends to limit collapse thereof ina direction longitudinally of the shell, saidmeans comprising an annularmember in the form of a helix engaging the inner face of the bend, theradius of the curve of the bend being greater than the radius of thecross-section of said member.

6. An expansible-collapsible element comprising a tubular metallic shellhaving circumferential corrugations formed of inward and outwardbendsconnected by intermediate transverse wall portions, and means located incertain of said bends to limit collapse thereof, said means comprisingan annular member in the form of a helical wire coil arranged inengagement with the inner face of a bend, said coil beingcircumferentially resilient.

7. An expansible-collapsible element comprising a tubular metallic shellhaving circumferential corrugations formed of inward and outward bendsconnected by intermediate transverse wall pprtions, and means located incertain of said bends to prevent collapse thereof longitudinally of theshell,

said means comprising an annular member in the form of a helical wirecoil engaging the inner face of a bend, said member being resilientcircumferentially and exerting its resilient force to hold it inposition in engagement with the inner face of the bend.

8. An expansible-collapsible element comprising a tubular metallic shellhaving circumferential corrugations formed of inward and outward bendsconnected by in termediate transverse wall portions, and means locatedin certain of said bends to prevent collapse thereof'in a directionlongitudinally of the shell, said means comprising a flexible andresilient Wire coil held y its resilience in engagement with the middleportion of the inner surface of the bend, and said coil being of suchthickness lengthwise of the element as to provide clearance spacesbetween the coil and the lateral portions of the bend.

' ward bends comprising 9. An expansible-collapsible element comprisinga tubular metallic shell having circumferential corrugations formed ofinward and outward bends connected by intermediate transverse wallportions, and means lo 10. An expansible-collapsible element comprisinga tubular metallic shell having circumferential corrugations formed ofinward and outward bends connected by intermediate transverse wallportions, and means located in certain of said inward bends and incertain of said outward bends to preventcollapse thereof in a directionlongitudinally of the shell, the means in said outa helical resilientannulus under circumferential compression whereby its resilience isexerted to holdit in position in engagement with the inner face of theouter bend, and said means in the innerbend consisting of an annularresilient helix exerting its resilience by contraction to hold it inengagement with the outer face of the inner bend.

11. An expansible-collapsible element comprising a tubular metallicshell having circumferential corrugations formed of inward and outwardbends connected by intermediate transverse wall portions, an annularfreely flexible spring member comprising a plurality of spaced apartinterconnected coils, said member being positioned Within an outer bendof said element and being of normal length greater than thecircumferential length of said element at said bend, whereby said memberis under circumferential compression and exerts a force radially of saidelement to maintain the member in engagement with the shell.

12. An expansible-collapsible element comprising a tubular metallicshell having member in engagement with the shell, and

a second annular freely flexible member comprising a plurality of spacedapart interconnected coils, said second member being positioned withinan inner bend of said element and being of normal length less than thecircumferential length of said element at said inner bend whereby saidmember is under circumferential tension and exerts a force radially ofsaid element to maintain the member in engagementwith the shell.

In testimony whereof I have hereunto Subscribed my name.

GEORGE BETHUNE DUFEIELD.

